We all know that routine vehicle maintenance, including oil changes, is crucial to keeping our cars running reliably and in as fuel-efficient a manner as possible. Using the best products for our vehicles and driving styles is important, but it can be hard to know which oil to choose, especially when there seem to be more brands available than ever before. Here are a few tips to help you choose the right oil for you.
First and foremost, check your owner’s manual for any manufacturer guidelines on oil choices, including any instructions on what not to use. The first two things to look for when buying motor oil are certifications that the product meets the current standards of the American Petroleum Institute (API). One of their certifications is indicated by a starburst symbol on the package; the other is the designation of “SL,” which refers to the oil’s ability to pass the latest engine and lab tests.
Choosing the right viscosity is your next task. Essentially, the viscosity rating tells you how much your oil will thicken under cold conditions (like being parked overnight during the winter) and how thin it will get under hot conditions (like when it’s running). You want oil that will stay thick enough to maintain the best seal and film of lubrication but thin enough to move freely. You’re probably familiar with oil weights being listed as 10W-30 or 5W-20 or maybe just SAE 30 (among other weights), but what do those numbers mean? The “W” stands for winter. The number before the W represents the oil’s viscosity at low temperatures; the second number indicates viscosity at higher (normal running) temps. If your winters are extremely cold, you’ll want to opt for a 5W or maybe a 10W, as these oils will stay thinner in extreme cold, which leads to quicker starts since the oil doesn’t have to warm up and thin out first. A higher second number is good because it means the oil will resist thinning too much at higher temps. A motor oil with “SAE” followed by a single number means it hasn’t been rated for use in winter conditions.
The other thing you’ll need to decide is whether you want a conventional, synthetic or synthetic blend. Conventional oil is derived directly from crude oil and is the kind of motor oil that’s been around the longest. Synthetic oil starts as conventional oil, but is modified to improve its lubricating and protective properties. Synthetic blends, not surprisingly, are a mix of the two. Synthetics are much more expensive than conventionals or blends and are designed for high-tech, high-performance engines. Typically, the added expense is completely unnecessary for most drivers. Synthetic blends have been formulated to better handle higher workloads and temperatures. They don’t cost much more than conventionals but do offer a bit of extra protection for drivers facing tougher conditions and drivers of higher workload trucks and SUVs. Today, there are even motor oils designed for vehicles with higher mileage, which can help older vehicles last even longer.
Understanding what motor oil is best for your car can help you feel more confident about your choice, whether you’re doing it yourself or just want to be sure the mechanic isn’t trying to oversell you the next time you bring your vehicle in for an oil change.